An electromagnetic pulse (EMP), also known as transient electromagnetic disturbance (TED), is a short burst of electromagnetic energy that can be generated naturally or artificially. It can interfere with communications and damage electronic equipment, and has the potential to cause physical destruction to objects such as buildings and aircraft. The first recorded instance of damage caused by an EMP was during the solar storm of August 1859, or the Carrington event. Managing the effects of an EMP is a branch of electromagnetic compatibility (EMC) engineering. A nuclear electromagnetic pulse (NEMP) is characterized by a rapid increase in intensity, reaching 90% of its maximum value in just four nanoseconds - much faster than a LEMP.
It is created when a nuclear weapon is detonated high above the Earth's surface. Andrei Sakharov first proposed the concept of a flow compression generator with explosive pumping to generate a non-nuclear EMP in 1951 in the Soviet Union. An EMP typically comprises many frequencies, from a very low limit to an upper limit depending on its source. To achieve the pulse frequency characteristics necessary for optimal coupling to the target, wave-forming circuits or microwave generators are added between the pulse source and the antenna. According to Maxwell's equations, a pulse of electrical energy will always be accompanied by a pulse of magnetic energy. Most EMPs have a very sharp edge of attack and build up quickly to their maximum level.
They usually send a pulse to any electrical connection present, in addition to radiating a pulse of energy. The compensation process implies that an energetic and highly excited system decays to the ground state by emitting an electromagnetic pulse. High-altitude EMPS (HEMP) are found twenty miles above Earth. Induced pulses have much lower energy than threat pulses, so they are more practical to create but less predictable. However, the pulses of a controlled switching circuit are usually roughly shaped like a rectangular or square pulse. Natural electromagnetic pulses include lightning, coronal mass ejections (CME), and electrostatic discharges.
